Item Has Already Been Added Error

3 posts, 0 answers
  1. Gohar
    Gohar avatar
    9 posts
    Member since:
    Dec 2015

    Posted 17 Dec 2015 Link to this post

    From filtering box, when I select Null and then select All then the following error occurs:

    Item has already been added. Key in dictionary: '(Blanks)'  Key being added: '(Blanks)'

    Please see the attached screenshot.

  2. Raphaël MANSUY
    Raphaël MANSUY avatar
    26 posts
    Member since:
    May 2005

    Posted 15 Mar in reply to Gohar Link to this post


    I have exactly the same issue.

    I've tried with the last version (2016 Q1) and I still have the problem.

    Is there a workaround available ?


    Thank you in advance

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  4. Dess
    Dess avatar
    1561 posts

    Posted 17 Mar Link to this post

    Hello Raphaël,

    Thank you for writing.

    I have logged it in our feedback portal. You can track its progress, subscribe for status changes and add your vote/comment to it on the following link - feedback item.

    I have also updated your Telerik points.

    Currently, the possible solution that I can suggest is to remove the unchecked node values from the dictionary: 

    this.radGridView1.FilterPopupInitialized += radGridView1_FilterPopupInitialized;
    RadListFilterDistinctValuesTable selectedValues;
    private void radGridView1_FilterPopupInitialized(object sender, Telerik.WinControls.UI.FilterPopupInitializedEventArgs e)
        RadListFilterPopup popup = e.FilterPopup as RadListFilterPopup;
        selectedValues = popup.MenuTreeElement.SelectedValues;
        popup.MenuTreeElement.TreeView.NodeCheckedChanged += TreeView_NodeCheckedChanged;
    private void TreeView_NodeCheckedChanged(object sender, TreeNodeCheckedEventArgs e)
        if (e.Node.CheckState == Telerik.WinControls.Enumerations.ToggleState.Off)
            if (selectedValues.Contains(e.Node.Text))

    I hope this information helps. Should you have further questions I would be glad to help.
    Do you need help with upgrading your AJAX, WPF or WinForms project? Check the Telerik API Analyzer and share your thoughts.
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